1. Field of Invention
The present invention is related to electrically heated nozzles for use with die casting. More specifically, to electrically heated nozzles for use with metal die casting.
2. History of Prior Art
The transfer of heated metal to die molds in the die casting industry was accomplished early on by the ladling of the metal to the mold. There was a tendency for the heated metal to cool during transfer which resulted in poor castings. Nozzles were developed to transfer heated metal to a mold through an enclosed device. This was an improvement, but there still was a substantial cooling of the heated metal sufficient to effect the mold. Also, the nozzles were not usable for all kinds of metals. Heated aluminum and magnesium quickly corroded the nozzles making them useless. Therefore, ladling is still in use for corrosive metals.
To overcome heated metal cooling within the nozzles, the nozzles are traditionally heated by using gas torches, such as blow torches. This method causes hot spots, and creates environmental problems, as well as fire hazards.
Efforts, to date, to electrically heat the nozzles have been less than successful. The electrically heated nozzles have been inefficient and expensive to use.
The electrically heated nozzle defined in the copendant application Ser. No. 07/692,114 is a substantial improvement over the prior art. The nozzle is an energy efficient nozzle which reduces heat loss. However, the nozzle, as defined, does not provide for processing the corrosive metals such as aluminum.
A nozzle, which is energy efficient, prevents heat loss, and can process any kind of heated metal under pressure, would provide greater environmental benefits and industrial uses. It is to all these goals that the present invention is directed.